Base64 encode and decode

A way to write binary data using 64 safe text characters (A–Z, a–z, 0–9, + and /). It is used to embed images in HTML or CSS, attach files to email and put binary data into JSON. It is an encoding, not encryption: anyone can decode it.

Yes. Text is converted to UTF-8 bytes before encoding, so any language and emoji round-trip correctly.

A variant that uses - and _ instead of + and / and drops the = padding, so the result can go in URLs and file names. JSON Web Tokens use it.